CVE-2026-20069Network attack vector

Cross-site scripting via client-side request smuggling

Published Mar 4, 2026 · Updated Mar 4, 2026

Client-side request smuggling in Cisco ASA and Secure FTD VPN web services allows remote attackers to inject browser-rendered content. The VPN HTTP request handler insufficiently validates crafted requests and reflects attacker-controlled input in a response rendered by the user’s browser. Exploitation requires enabled SSL VPN or IKEv2 client services and a user visit to an attacker-controlled site; it enables browser attacks such as XSS but does not directly affect the firewall device.

CVSS severity4.3
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Client-side request smuggling in Cisco ASA and Secure FTD VPN web services allows remote attackers to inject browser-rendered content. The VPN HTTP request handler insufficiently validates crafted requests and reflects attacker-controlled input in a response rendered by the user’s browser. Exploitation requires enabled SSL VPN or IKEv2 client services and a user visit to an attacker-controlled site; it enables browser attacks such as XSS but does not directly affect the firewall device.

The record

CVE
CVE-2026-20069
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-444, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.12.1
  2. Affected versionversion=9.12.1.2
  3. Affected versionversion=9.12.1.3
  4. Affected versionversion=9.12.2
  5. Affected versionversion=9.12.2.1
  6. Affected versionversion=9.12.2.4
  7. Affected versionversion=9.12.2.5
  8. Affected versionversion=9.12.2.9
  9. Affected versionversion=9.12.3
  10. Affected versionversion=9.12.3.12
  11. Affected versionversion=9.12.3.2
  12. Affected versionversion=9.12.3.7
  13. Affected versionversion=9.12.3.9
  14. Affected versionversion=9.12.4
  15. Affected versionversion=9.12.4.10
  16. Affected versionversion=9.12.4.13
  17. Affected versionversion=9.12.4.18
  18. Affected versionversion=9.12.4.2
  19. Affected versionversion=9.12.4.24
  20. Affected versionversion=9.12.4.26
  21. Affected versionversion=9.12.4.29
  22. Affected versionversion=9.12.4.30
  23. Affected versionversion=9.12.4.35
  24. Affected versionversion=9.12.4.37
  25. Affected versionversion=9.12.4.38
  26. Affected versionversion=9.12.4.39
  27. Affected versionversion=9.12.4.4
  28. Affected versionversion=9.12.4.40
  29. Affected versionversion=9.12.4.41
  30. Affected versionversion=9.12.4.47
  31. Affected versionversion=9.12.4.48
  32. Affected versionversion=9.12.4.50
  33. Affected versionversion=9.12.4.52
  34. Affected versionversion=9.12.4.54
  35. Affected versionversion=9.12.4.55
  36. Affected versionversion=9.12.4.56
  37. Affected versionversion=9.12.4.58
  38. Affected versionversion=9.12.4.62
  39. Affected versionversion=9.12.4.65
  40. Affected versionversion=9.12.4.67
  41. Affected versionversion=9.12.4.7
  42. Affected versionversion=9.12.4.8
  43. Affected versionversion=9.16.1
  44. Affected versionversion=9.16.1.28
  45. Affected versionversion=9.16.2
  46. Affected versionversion=9.16.2.11
  47. Affected versionversion=9.16.2.13
  48. Affected versionversion=9.16.2.14
  49. Affected versionversion=9.16.2.3
  50. Affected versionversion=9.16.2.7
  51. Affected versionversion=9.16.3
  52. Affected versionversion=9.16.3.14
  53. Affected versionversion=9.16.3.15
  54. Affected versionversion=9.16.3.19
  55. Affected versionversion=9.16.3.23
  56. Affected versionversion=9.16.3.3
  57. Affected versionversion=9.16.4
  58. Affected versionversion=9.16.4.14
  59. Affected versionversion=9.16.4.19
  60. Affected versionversion=9.16.4.27
  61. Affected versionversion=9.16.4.38
  62. Affected versionversion=9.16.4.39
  63. Affected versionversion=9.16.4.42
  64. Affected versionversion=9.16.4.48
  65. Affected versionversion=9.16.4.55
  66. Affected versionversion=9.16.4.57
  67. Affected versionversion=9.16.4.61
  68. Affected versionversion=9.16.4.62
  69. Affected versionversion=9.16.4.67
  70. Affected versionversion=9.16.4.70
  71. Affected versionversion=9.16.4.71
  72. Affected versionversion=9.16.4.76
  73. Affected versionversion=9.16.4.82
  74. Affected versionversion=9.16.4.84
  75. Affected versionversion=9.16.4.9
  76. Affected versionversion=9.17.1
  77. Affected versionversion=9.17.1.10
  78. Affected versionversion=9.17.1.11
  79. Affected versionversion=9.17.1.13
  80. Affected versionversion=9.17.1.15
  81. Affected versionversion=9.17.1.20
  82. Affected versionversion=9.17.1.30
  83. Affected versionversion=9.17.1.33
  84. Affected versionversion=9.17.1.39
  85. Affected versionversion=9.17.1.45
  86. Affected versionversion=9.17.1.46
  87. Affected versionversion=9.17.1.7
  88. Affected versionversion=9.17.1.9
  89. Affected versionversion=9.18.1
  90. Affected versionversion=9.18.1.3
  91. Affected versionversion=9.18.2
  92. Affected versionversion=9.18.2.5
  93. Affected versionversion=9.18.2.7
  94. Affected versionversion=9.18.2.8
  95. Affected versionversion=9.18.3
  96. Affected versionversion=9.18.3.39
  97. Affected versionversion=9.18.3.46
  98. Affected versionversion=9.18.3.53
  99. Affected versionversion=9.18.3.55
  100. Affected versionversion=9.18.3.56
  101. Affected versionversion=9.18.4
  102. Affected versionversion=9.18.4.22
  103. Affected versionversion=9.18.4.24
  104. Affected versionversion=9.18.4.29
  105. Affected versionversion=9.18.4.34
  106. Affected versionversion=9.18.4.40
  107. Affected versionversion=9.18.4.47
  108. Affected versionversion=9.18.4.5
  109. Affected versionversion=9.18.4.50
  110. Affected versionversion=9.18.4.52
  111. Affected versionversion=9.18.4.53
  112. Affected versionversion=9.18.4.57
  113. Affected versionversion=9.18.4.8
  114. Affected versionversion=9.19.1
  115. Affected versionversion=9.19.1.12
  116. Affected versionversion=9.19.1.18
  117. Affected versionversion=9.19.1.22
  118. Affected versionversion=9.19.1.24
  119. Affected versionversion=9.19.1.27
  120. Affected versionversion=9.19.1.28
  121. Affected versionversion=9.19.1.31
  122. Affected versionversion=9.19.1.37
  123. Affected versionversion=9.19.1.38
  124. Affected versionversion=9.19.1.42
  125. Affected versionversion=9.19.1.5
  126. Affected versionversion=9.19.1.9
  127. Affected versionversion=9.20.1
  128. Affected versionversion=9.20.1.5
  129. Affected versionversion=9.20.2
  130. Affected versionversion=9.20.2.10
  131. Affected versionversion=9.20.2.21
  132. Affected versionversion=9.20.2.22
  133. Affected versionversion=9.20.3
  134. Affected versionversion=9.20.3.10
  135. Affected versionversion=9.20.3.13
  136. Affected versionversion=9.20.3.16
  137. Affected versionversion=9.20.3.20
  138. Affected versionversion=9.20.3.4
  139. Affected versionversion=9.20.3.7
  140. Affected versionversion=9.20.3.9
  141. Affected versionversion=9.20.4
  142. Affected versionversion=9.22.1.1
  143. Affected versionversion=9.22.1.2
  144. Affected versionversion=9.22.1.3
  145. Affected versionversion=9.22.1.6
  146. Affected versionversion=9.22.2
  147. Affected versionversion=9.22.2.4
  148. Affected versionversion=9.22.2.9
  149. Affected versionversion=9.23.1
  150. Affected versionversion=9.23.1.3
  151. Affected versionversion=9.23.1.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.12.1; version=9.12.1.2; version=9.12.1.3; version=9.12.2; version=9.12.2.1; version=9.12.2.4; version=9.12.2.5; version=9.12.2.9; version=9.12.3; version=9.12.3.12; version=9.12.3.2; version=9.12.3.7; version=9.12.3.9; version=9.12.4; version=9.12.4.10; version=9.12.4.13; version=9.12.4.18; version=9.12.4.2; version=9.12.4.24; version=9.12.4.26; version=9.12.4.29; version=9.12.4.30; version=9.12.4.35; version=9.12.4.37; version=9.12.4.38; version=9.12.4.39; version=9.12.4.4; version=9.12.4.40; version=9.12.4.41; version=9.12.4.47; version=9.12.4.48; version=9.12.4.50; version=9.12.4.52; version=9.12.4.54; version=9.12.4.55; version=9.12.4.56; version=9.12.4.58; version=9.12.4.62; version=9.12.4.65; version=9.12.4.67; version=9.12.4.7; version=9.12.4.8; version=9.16.1; version=9.16.1.28; version=9.16.2; version=9.16.2.11; version=9.16.2.13; version=9.16.2.14; version=9.16.2.3; version=9.16.2.7; version=9.16.3; version=9.16.3.14; version=9.16.3.15; version=9.16.3.19; version=9.16.3.23; version=9.16.3.3; version=9.16.4; version=9.16.4.14; version=9.16.4.19; version=9.16.4.27; version=9.16.4.38; version=9.16.4.39; version=9.16.4.42; version=9.16.4.48; version=9.16.4.55; version=9.16.4.57; version=9.16.4.61; version=9.16.4.62; version=9.16.4.67; version=9.16.4.70; version=9.16.4.71; version=9.16.4.76; version=9.16.4.82; version=9.16.4.84; version=9.16.4.9; version=9.17.1; version=9.17.1.10; version=9.17.1.11; version=9.17.1.13; version=9.17.1.15; version=9.17.1.20; version=9.17.1.30; version=9.17.1.33; version=9.17.1.39; version=9.17.1.45; version=9.17.1.46; version=9.17.1.7; version=9.17.1.9; version=9.18.1; version=9.18.1.3; version=9.18.2; version=9.18.2.5; version=9.18.2.7; version=9.18.2.8; version=9.18.3; version=9.18.3.39; version=9.18.3.46; version=9.18.3.53; version=9.18.3.55; version=9.18.3.56; version=9.18.4; version=9.18.4.22; version=9.18.4.24; version=9.18.4.29; version=9.18.4.34; version=9.18.4.40; version=9.18.4.47; version=9.18.4.5; version=9.18.4.50; version=9.18.4.52; version=9.18.4.53; version=9.18.4.57; version=9.18.4.8; version=9.19.1; version=9.19.1.12; version=9.19.1.18; version=9.19.1.22; version=9.19.1.24; version=9.19.1.27; version=9.19.1.28; version=9.19.1.31; version=9.19.1.37; version=9.19.1.38; version=9.19.1.42; version=9.19.1.5; version=9.19.1.9; version=9.20.1; version=9.20.1.5; version=9.20.2; version=9.20.2.10; version=9.20.2.21; version=9.20.2.22; version=9.20.3; version=9.20.3.10; version=9.20.3.13; version=9.20.3.16; version=9.20.3.20; version=9.20.3.4; version=9.20.3.7; version=9.20.3.9; version=9.20.4; version=9.22.1.1; version=9.22.1.2; version=9.22.1.3; version=9.22.1.6; version=9.22.2; version=9.22.2.4; version=9.22.2.9; version=9.23.1; version=9.23.1.3; version=9.23.1.7
ClamAV · Cisco Secure Firewall Threat Defenseversion=6.4.0; version=6.4.0.1; version=6.4.0.10; version=6.4.0.11; version=6.4.0.12; version=6.4.0.13; version=6.4.0.14; version=6.4.0.15; version=6.4.0.16; version=6.4.0.17; version=6.4.0.18; version=6.4.0.2; version=6.4.0.3; version=6.4.0.4; version=6.4.0.5; version=6.4.0.6; version=6.4.0.7; version=6.4.0.8; version=6.4.0.9; version=7.0.0; version=7.0.0.1; version=7.0.1; version=7.0.1.1; version=7.0.2; version=7.0.2.1; version=7.0.3; version=7.0.4; version=7.0.5; version=7.0.6; version=7.0.6.1; version=7.0.6.2; version=7.0.6.3; version=7.0.7; version=7.0.8; version=7.0.8.1; version=7.1.0; version=7.1.0.1; version=7.1.0.2; version=7.1.0.3; version=7.2.0; version=7.2.0.1; version=7.2.1; version=7.2.10; version=7.2.10.2; version=7.2.2; version=7.2.3; version=7.2.4; version=7.2.4.1; version=7.2.5; version=7.2.5.1; version=7.2.5.2; version=7.2.6; version=7.2.7; version=7.2.8; version=7.2.8.1; version=7.2.9; version=7.3.0; version=7.3.1; version=7.3.1.1; version=7.3.1.2; version=7.4.0; version=7.4.1; version=7.4.1.1; version=7.4.2; version=7.4.2.1; version=7.4.2.2; version=7.4.2.3; version=7.4.2.4; version=7.6.0; version=7.6.1; version=7.6.2; version=7.6.2.1; version=7.7.0; version=7.7.10; version=7.7.10.1

Published CVSS scores

4.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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